WHBM,
The crew started in Dublin, Gatwick was a turnaround. The flight sequence was DUB-LGW-NOC. All docs would have been obtained in Dublin.
Unfortunately, as far as the CAA is concerned, it was an Irish aeroplane operating in Irish airspace when the incident occured. Had it occured on the approach to a UK airport, then they could intervene.
One expects that the CAA might ask tougher questions than the IAA, so more's the pity they have no jurisdiction in this matter.